NFT with mechanically robust materials

ABSTRACT

A recording head includes a near-field transducer proximate a media-facing surface. The near-field transducer comprises an aperture portion surrounded by walls of plasmonic material, the walls oriented normal to the media-facing surface. A notch protrudes within the aperture. The notch comprises at least one of Rh and Ir. A write pole is proximate the near-field transducer. The write pole has a back surface facing away from the media-facing surface and an aperture-facing surface proximate the aperture.

RELATED PATENT DOCUMENTS

This application is a continuation of U.S. patent application Ser. No.15/980,293, filed on May 15, 2018 which is a continuation of U.S. patentapplication Ser. No. 15/443,188, filed on Feb. 27, 2017, now U.S. Pat.No. 9,972,346, which claims the benefit of Provisional PatentApplication No. 62/300,796 filed on Feb. 27, 2016, which areincorporated herein by reference in their entireties. U.S. patentapplication Ser. No. 15/166,799, filed on May 27, 2016 which claims thebenefit of Provisional Patent Application No. 62/300,796 filed on Feb.27, 2016 are also herein incorporated by reference in their entireties.

SUMMARY

Embodiments described herein involve a recording head comprising anear-field transducer proximate a media-facing surface. The near-fieldtransducer comprises an aperture portion surrounded by walls ofplasmonic material, the walls oriented normal to the media-facingsurface. A notch protrudes within the aperture. The notch comprises atleast one of Rh and Ir. A write pole is proximate the near-fieldtransducer. The write pole has a back surface facing away from themedia-facing surface and an aperture-facing surface proximate theaperture.

Embodiments described herein involve a recording head comprising anear-field transducer proximate a media-facing surface. The near-fieldtransducer comprises an aperture portion surrounded by walls ofplasmonic material, the walls oriented normal to the media-facingsurface. At least two notches protrude within the aperture, the at leasttwo notches comprising at least one of Rh and Ir. A write pole isproximate the near-field transducer. The write pole has a back surfacefacing away from the media-facing surface and an aperture-facing surfaceproximate the aperture.

Embodiments described herein involve a method comprising propagatinglight via a waveguide from an energy source to a near-field transducernear a media-facing surface of a recording head. Surface plasmons areexcited along walls of an aperture of the near-field transducer andalong a notch protruding within the aperture. The walls are formed of aplasmonic material and are oriented normal to the media-facing surface.The walls and the notch direct the surface plasmons to a recordingmedium. The notch comprises at least one of Rh and Ir. A magnetic fieldis generated at the recording medium via a write pole proximate thenear-field transducer. The write pole has a back surface facing awayfrom the media-facing surface and an aperture-facing surface proximatethe aperture.

The above summary is not intended to describe each disclosed embodimentor every implementation of the present disclosure. The figures and thedetailed description below more particularly exemplify illustrativeembodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

Throughout the specification reference is made to the appended drawings,where like reference numerals designate like elements, and wherein:

FIG. 1 is a perspective view of a hard drive slider that includes awaveguide in accordance with embodiments described herein;

FIGS. 2A-2E are a cross-sectional views showing details of a HAMRapparatus in accordance with embodiments described herein;

FIG. 3 is a perspective view of a near-field transducer according to anillustrative embodiment;

FIG. 4 is a perspective view of a near-field transducer according to anillustrative embodiment;

FIGS. 5-16 are each diagrams showing multiple views of near-fieldtransducer arrangements according to additional illustrativeembodiments;

FIGS. 17A and 17B are graphs showing the effective of the real andimaginary parts of the permittivity of the peg material on the pegtemperature (FIG. 17A) and the cross track erasure (FIG. 17B);

FIGS. 18A-18E show diagrams including optional adhesion layers inpossible illustrative configurations;

FIGS. 19A-19C show views of an aperture NFT in accordance withembodiments described herein;

FIGS. 19D and 19E show vies of an aperture NFT having two notches inaccordance with embodiments described herein;

FIG. 20 shows a cross-sectional perspective view shows an aperture NFTin accordance with embodiments described herein;

FIGS. 21A-21C illustrate view of an aperture NFT where all or a portionof the notch comprises a mechanically robust material in accordance withembodiments described herein;

FIGS. 22A-22C illustrate views of an aperture NFT having a coatingcomprising mechanically robust materials in accordance with embodimentsdescribed herein;

FIGS. 23A-23C illustrate views of an aperture NFT having a first portioncomprising a mechanically robust material;

FIGS. 24A-24C illustrate views of an NFT having a notch comprisingmechanically robust materials and a coating disposed on the notch inaccordance with various embodiments described herein;

FIGS. 25A-25C illustrate an aperture NFT having a notch coated with amechanically robust material according to various embodiments;

FIGS. 26A-26C illustrate views of a PPG NFT accordance with variousembodiments described herein;

FIGS. 27A, 27B, and 28 illustrate embodiments of a PPG NFT having a pegcomprising a mechanically robust material;

FIGS. 29A-29C illustrate a PPG NFT system for use with TE propagatinglight in accordance with embodiments described herein;

FIGS. 30A and 30B show views of a gap NFT in accordance with embodimentsdescribed herein;

FIGS. 31A-31C illustrate views of a gap NFT having an inner core portionmade from a mechanically robust material in accordance with embodimentsdescribed herein;

FIGS. 32A-32C show views of a gap NFT having a top surface made from amechanically robust material in accordance with embodiments describedherein;

FIGS. 33A-33C illustrate views of a gap NFT having a small corner madefrom a mechanically robust material in accordance with embodimentsdescribed herein;

FIGS. 34A-34C show views of a gap NFT having a small corner coated witha mechanically robust material in accordance with various embodimentsdescribed herein;

FIGS. 35A-35C illustrate views of another type of gap NFT in accordancewith embodiments described herein;

FIGS. 36A-36C show views of a gap NFT having a small corner made from amechanically robust material in accordance with embodiments describedherein;

FIGS. 37A-37C illustrate views of an edge made from a mechanicallyrobust material in accordance with embodiments described herein;

FIGS. 38A-38C show views of a gap NFT having a corner made from amechanically robust material in accordance with embodiments describedherein;

FIGS. 39A-39C show views of a gap NFT having a corner coated with amechanically robust material in accordance with embodiments describedherein;

FIGS. 40A-40C illustrate a gap NFT system for use with TE propagatinglight in accordance with embodiments described herein;

FIGS. 41A-41D illustrate views of a lollipop NFT in accordance withembodiments described herein;

FIGS. 42A and 42B show views of a lollipop NFT having a peg extend undera disc and made from a mechanically robust material in accordance withembodiments described herein;

FIGS. 43A and 43B illustrate views of a lollipop NFT having a pegextending into a disc and made from a mechanically robust material inaccordance with embodiments described herein;

FIGS. 44A and 44B show views of a lollipop NFT having a peg that isdisposed on the disc and is made from a mechanically robust material inaccordance with embodiments described herein; and

FIGS. 45A and 45B illustrate views of a lollipop NFT having a peg thatis abutted to the disc and is made from a mechanically robust materialin accordance with embodiments described herein.

The figures are not necessarily to scale. Like numbers used in thefigures refer to like components. However, it will be understood thatthe use of a number to refer to a component in a given figure is notintended to limit the component in another figure labeled with the samenumber.

DETAILED DESCRIPTION

The present disclosure is generally directed to read-write heads used inmagnetic recording devices such as hard drives. In particular, thisdisclosure relates to heat-assisted magnetic recording (HAMR), which canbe used to increase areal data density of magnetic media. In a HAMRdevice, information bits are recorded in a storage layer at elevatedtemperatures in a specially configured magnetic media. The use of heatcan overcome superparamagnetic effects that might otherwise limit theareal data density of the media. As such, HAMR devices may include nearfield transducers (NFTs) for delivering electromagnetic energy to aconfined area of a rotating media, the area (spot size) exposed to theelectromagnetic energy is heated, at the same time the magnetic writehead applies a magnetic field to the media for recording.

A HAMR read/write element, sometimes referred to as a slider, recordinghead, read head, write head, read/write head, etc., includes magneticread and write transducers similar to those on current hard drives. Forexample, data may be read by a magnetoresistive sensor that detectsmagnetic fluctuations of a magnetic media as it moves underneath thesensor. Data is written to the magnetic media by a write coil that ismagnetically coupled to a write pole. The write pole changes magneticorientation in regions of the media as it moves underneath the writepole in response to an energizing current applied to the write coil. AHAMR slider will also generally include a source of energy, such as alaser diode, to heat the media while it is being written to by the writepole. An optical delivery path is integrated into the HAMR slider todeliver the energy to the surface of the media.

The optical delivery path of a HAMR slider may include a plasmonictransducer proximate a media-facing surface (e.g., air-bearing surface,contact surface). The plasmonic transducer shapes and transmits theenergy to a small region on the medium. The plasmonic transducer issometimes referred to as a near-field transducer (NFT), optical antenna,surface plasmon resonator, etc., and may include a plasmonic metal suchas gold, silver, copper, aluminum, etc., and alloys thereof. Theplasmonic transducer for a HAMR device is very small (e.g., on the orderof 0.1 to a few light wavelengths, or any value therebetween) andcreates a localized region of high power density in the media through anelectromagnetic interaction. This results in a high temperature rise ina small region on the media, with the region exceeding the Curietemperature having dimensions less than 100 nm.

Due to the intensity of the laser light and the small size of the NFT,the NFT and surrounding material are subject to a significant rise intemperature during writing. Over time, this can affect the integrityand/or reliability of the NFT, for example, causing it to becomemisshapen or recess, undergo chemical changes, migrate, diffuse orotherwise be altered in a way that prevents effective coupling of energyfrom the near field transducer into the media. Other events, such ascontact between the read/write head and recording medium, contamination,etc., may also degrade the operation of the NFT and nearby opticalcomponents. Degradation of the NFT will affect the effective servicelife of a HAMR read/write head. In view of this, methods and apparatusesdescribed herein are used to increase the thermal and/or mechanicalrobustness of the NFT, such as at a peg that extends towards therecording media. A thermally robust material may be referred to hereinas a mechanically robust material and/or a hard material and/or achemically robust material. Chemical robustness may indicate aresistance to chemical change in the presence of oxidizers, acids,bases, etc.

In reference to FIG. 1, a perspective view shows a HAMR slider assembly100 according to an example embodiment. The slider assembly 100 includesa laser diode 102 located on input surface 103 of a slider body 101. Inthis example, the input surface 103 is a top surface, which is locatedopposite to a media-facing surface 108 that is positioned over a surfaceof a recording media (not shown) during device operation. Themedia-facing surface 108 faces and is held proximate to the moving mediasurface while reading and writing to the media. The media-facing surface108 may be configured as an air-bearing surface (ABS) that maintainsseparation from the media surface via a thin layer of air.

The laser diode 102 delivers light to a region proximate a HAMRread/write head 106, which is located near the media-facing surface 108.The energy is used to heat the recording media as it passes by theread/write head 106. Optical coupling components, which may include amode converting waveguide system 110, are formed integrally within theslider body 101 (near a trailing edge surface 104 in this example) andfunction as an optical path that delivers energy from the laser diode102 to the recording media via a near-field transducer (NFT) 112. TheNFT 112 is near the read/write head 106 and causes heating of the mediaduring recording operations.

The laser diode 102 in this example may be configured as either anedge-emitting laser or surface-emitting laser. Generally, theedge-emitting laser emits light from near a corner edge of the laser anda surface emitting laser emits light in a direction perpendicular to asurface of the laser body, e.g., from a point near a center of thesurface. An edge-emitting laser may be mounted on the top surface 103 ofthe slider body 101 (e.g., in a pocket or cavity) such that the light isemitted in a direction parallel to (or at least non-perpendicular to)the media-facing surface. A surface-emitting or edge-emitting laser inany of these examples may be directly coupled to the slider body 101, orvia an intermediary component such as a submount (not shown). A submountcan be used to orient an edge-emitting laser so that its output isdirectly downwards (negative y-direction in the figure).

While the example in FIG. 1 shows a laser diode 102 directly mounted tothe slider body 101, the waveguide system 110 discussed herein may beapplicable to any type of light delivery configuration. For example, alaser may be mounted on the trailing edge surface 104 instead of the topsurface 103. In another configuration known as free-space lightdelivery, a laser may be mounted external to the slider 100, and coupledto the slider by way of optic fiber and/or waveguide. An input surfaceof the slider body 101 may include a grating or other coupling featureto receive light from the laser via the optic fiber and/or waveguide.

In reference now to FIGS. 2A-2E, cross-sectional views show details ofHAMR devices 106 a-106 e according to example embodiments. FIGS. 2A-2Eshow different NFT 112-112 e configurations. The NFT 112 a-112 e islocated proximate a media-facing surface 108 (e.g., ABS), which is heldnear a magnetic recording media 202 during device operation. The NFT 112a-112 e may include a heat sink 207 a-207 d that draws away some heat,e.g., to the write pole 206 or other nearby heat-conductive component.The media-facing surface 108 is arranged parallel to the x-z plane. Awaveguide core 210 may be disposed proximate the NFT 112 a-112 e, whichis located at or near the media writing surface 108.

The waveguide core 210 surrounded by cladding layers 212, 214. Thewaveguide core 210 and cladding layers 212, 214 may be made fromdielectric materials such as Al₂O₃, SiO_(x)N_(y), SiO₂, Ta₂O₅, TiO₂,ZnS, SiN_(x), Nb₂O₅, AlN, Hf₂O₃, Y₂O₃, Al_(x)O_(y), etc. Generally, thedielectric materials are selected so that the refractive index of thewaveguide core layer 210 is higher than refractive indices of thecladding layers 212, 214. This arrangement of materials facilitatesefficient propagation of light through the waveguide. Light is deliveredfrom the waveguide core 210 along the negative y-direction where it iscoupled to the NFT 112 a-112 e. The NFT 112 a-112 e delivers surfaceplasmon enhanced, near-field electromagnetic energy along the y-axiswhere it exits at the media writing surface 202. This may result in ahighly localized hot spot 208 on the media surface 202 when the media204 placed in close proximity to surface 202 of the apparatus 106 a-106e. Further illustrated in FIGS. 2A-2E is a recording pole 206 of theread/write head that is located alongside the NFT 112 a-112 e. Therecording pole 206 generates a magnetic field (e.g., perpendicularfield) used in changing the magnetic orientation of the hotspot 208during writing.

In FIG. 3, a perspective views show details of a device including a NFT.The device 112 can include two parts: a disc 300 and a heat sink 302proximate to (e.g., deposited directly on to) the disc 300. In thisexample, the outline of the disc 300 on the xz-plane (which is asubstrate-parallel plane) is enlarged relative to the heat sink 302,although they may be the same size. The heat sink 302 can include anangled surface 302 a that is located proximate to a write pole (see,e.g., write pole 206 in FIG. 2) or other heat sinking infrastructure.

The disc 300 includes a top disc 300 a that acts as a collector ofoptical energy from a waveguide and/or focusing element. The disc 300achieves surface plasmon resonance in response to the optical energy andthe surface plasmon energy is directed to the medium via a peg 300 bthat extends from the disc 300. It should be noted that the heat sinkmay also contribute to the energy transfer process and in some suchembodiments a NFT does not necessarily include a separate disc and heatsink but a single component that can act as both. In this example, thedisc 300 is configured as an elongated plate with rounded (e.g.,circular) ends, also referred to as a stadium or capsule shape. Otherenlarged portion geometries may be used, including circular,rectangular, triangular, ellipsoidal, parabolic etc.

In FIG. 4, a perspective views show details of a device 412 according toan example embodiment. The device 412 includes a NFT 405 and a heat sink402 proximate to (e.g., deposited directly on to) the disc 400 of theNFT 405. In this example, the outline of the disc 400 on the xz-plane(which is a substrate-parallel plane) is enlarged relative to the heatsink 402, although they may be the same size. The heat sink 402 includesan angled surface 402 a that is located proximate to a write pole (see,e.g., write pole 206 in FIG. 2) or other heat sinking infrastructure.

The disc 400 includes a top disc 400 a that acts as a collector ofoptical energy from a waveguide and/or focusing element. The top disc400 a achieves surface plasmon resonance in response to the opticalenergy and the surface plasmon energy is directed to the medium via apeg 400 b that extends from top portion 400 a. In this example, the topportion 400 a is configured as an elongated plate with rounded (e.g.,circular) ends, also referred to as a stadium or capsule shape. Otherenlarged portion geometries may be used, including circular,rectangular, triangular, ellipsoidal, parabolic etc.

The disc 400 also includes a bottom disc 400 c. The bottom disc 400 ccan also be referred to as a sunken disc. The term “sunken disc” refersto a base or bottom portion that extends below the peg, as shown by thebase portion 400 c in FIG. 3. This can also be described as the pegextending beyond the bottom disc 400 c. In some embodiments, such asthat depicted in FIG. 4, the bottom disc 400 c and the top disc 400 acan have the same outline shape (e.g., stadium shape) as well as a sameoutline size. In some embodiments, the bottom disc 400 c and the topdisc 400 a can have different outline shapes, different outline sizes,or combinations thereof. The peg 400 b extends beyond the bottom disc400 c. The bottom portion 400 c is disposed proximate a light deliverystructure (e.g., a waveguide core) and away from a write pole. In someembodiments, the bottom disc 400 c may likely be, but need not be, theprimary collector of optical energy.

In FIGS. 5-16, composite views show NFT configurations according toadditional embodiments. For purposes of convenience, the write pole andmedia-facing surface are assigned reference numbers 902 and 900,respectively in all of FIGS. 5-16. In each of FIGS. 5-16, view (a) is aplan view of a substrate-parallel plane of an NFT, heat sink, and writepole 902 near a media-facing surface 900, where the write pole 902 is atthe bottom. In these figures, view (b) is a plan view of just the NFT,and view (c) is a side view of an NFT, heat sink, and write pole 902near a media-facing surface 900. In each case, the size and shape,relative position and material of both the base portions and associatedpegs are chosen such that the base portions convert incident photonsinto plasmons. It should be noted herein that “base portions” can besimilar to “discs” as referred to elsewhere in this application. Theplasmon is coupled from the base portions to the pegs, the pegs couplingenergy into a magnetic storage medium.

In the embodiments of FIGS. 5-16, based portions, pegs, and heatsinksmay be made of similar, identical or distinct materials. In particularembodiments, the pegs may be made of a thermally robust and/orchemically robust material described above and the base portions andheat sinks may be made of plasmonic materials. In some cases, the heatsink has high thermal conductivity. Also, in the embodiments shown inFIGS. 5-16 where the peg is embedded in a base portion, the baseportions may include recesses that expose a top side of the peg, and thepeg may have a thickness that is less than that of the base portion inwhich the peg is embedded. Any of the embodiments shown in FIGS. 5-16may also be used with a waveguide (e.g., waveguide core) proximate thebase portion(s), and may also include a plasmonic disc that is locatedon a side of the waveguide that faces away from the base portion(s).

In FIG. 5, an NFT includes a disc-style base portion 904 and a peg 906.The peg 906 is rod-shaped and extends to a middle of the base portion904. The base portion 904 is has a circular contour/outline in thisexample, although a stadium or other topographically similar shapes mayalso be used. A heat sink 908 has a contour/outline that follows that ofthe base portion 904 (circular outline in this example, although couldbe stadium shaped when used with a stadium-shaped or othertopographically similarly shaped base portion) and extends from a majorsurface of the base portion 904 to the write pole 902. The heat sink 908has a smaller contour than the base portion 904 in this example,although the heat sink's contour may be the same size as that of thebase portion 904 in some embodiments. A lower base portion 910 mayoptionally be used. The lower base portion 910 extends from a secondmajor surface of the base portion 904 away from the heat sink 902. Anouter surface of the lower base portion 910 may be proximate a lightdelivery structure, e.g., waveguide (not shown).

In FIG. 6, an NFT includes a circular disc-shaped base portion 1004 anda peg 1006. The peg 1006 has a flared end 1006 a that extends to amiddle of the base portion 1004. The flared end 1006 a is a geometricalstructure that improves adhesion and/or thermal transport and/orplasmonic coupling between the peg 1006 and base portion 1004. A stadiumshape may instead be used for the outer contours of the base portion1004. A heat sink 1008 has a contour that follows that of the baseportion 1004 and extends from a major surface of the base portion 1004to the write pole 902. The heat sink 1008 has a smaller contour than thebase portion 1004 in this example, although its contour may be the samesize as that of the base portion 1004 in some embodiments. A lower baseportion 1010 may optionally be used similar to the lower base portion910 in the description of FIG. 5.

In FIG. 7, an NFT includes a crescent-shaped base portion 1104 and a peg1106. The base portion 1104 has a crescent shape in this example,although other shapes may be used, e.g. a stadium, rectangle or othertopographically similar shapes. The peg 1106 has a flared end 1106 athat extends towards the base portion 1104, however the peg 1106 andbase portion 1104 are not joined directly together. The flared end 1106a is a geometrical structure that improves plasmonic coupling betweenthe peg 1106 and base portion 1104. A heat sink 1108 joins the baseportion 1104, the peg 1106 the write pole 902. The heat sink 1108 has anoval shape in this example, although other shapes may be used, e.g., ashape that follows the contour of the base portion 1104 at one end.

In FIG. 8, an NFT includes a crescent-shaped base portion 1204 and a peg1206. The base portion 1204 has a crescent shape in this example,although other shapes may be used, e.g. a stadium, rectangle or othertopographically similar shapes. The peg 1206 has a flared end 1206 athat extends towards the base portion 1204. The peg 1206 and baseportion 1204 are not joined directly together. The flared end 1206 a isa geometrical structure that improves plasmonic coupling between the rod1206 and base portion 1204. A first heat sink 1208 joins the peg 1206 tothe write pole 902, and second heat sink 1209 joins the base portion1204 to the write pole 902. The heat sinks 1208, 1209 have oval andround shapes in this example, although other shapes may be used. For theshape of heat sink 1209 may follow that of the base portion 1204.

In FIG. 9, an NFT includes two crescent-shaped base portions 1304, 1305separated by a gap. The base portions 1304, 1305 have a crescent shapein this example, although other shapes may be used, e.g. a stadium,rectangle or other topographically equivalent shapes, designed toenhance the coupling of light from the waveguide (not shown) to thesurface plasmon. The peg 1306 has a flared end 1306 a that extendstowards the gap between the base portions 1304, 1305 however the peg1306 and base portions 1304, 1305 are not joined directly together. Theflared end 1306 a is a geometrical structure that improves plasmoniccoupling between the rod 1306 and base portions 1304, 1305. A first heatsink 1308 joins the peg 1306 to the write pole 902, and second heatsinks 1309, 1310 join the base portions 1304, 1305 to the write pole902. The heat sinks 1308-1310 have oval and round shapes in thisexample, although other shapes may be used. For the shape of heat sinks1309, 1310 may follow that of the respective base portions 1304, 1305.

In FIG. 10, an NFT includes two crescent-shaped base portions 1404, 1405separated by a gap. The base portions 1404, 1405 have a crescent shapein this example, although other shapes may be used, e.g. a stadium,rectangle or other topographically equivalent shapes, designed toenhance the coupling of light from the waveguide (not shown) to thesurface plasmon. The peg 1406 has a flared end 1406 a that extendstowards the gap between the base portions 1404, 1405. The peg 1406 andbase portions 1404, 1405 are not joined directly together. The flaredend 1406 a is a geometrical structure that improves plasmonic couplingbetween the rod 1406 and base portion 1404. A first heat sink 1408 joinsthe peg 1406 to the write pole 902, and second heat sink 1409 joins thebase portions 1404, 1405 to the write pole 902. The heat sinks 1408,1409 have oval and round shapes in this example, although other shapesmay be used. For the shape of heat sink 1409 may follows that of thebase portions 1404, 1405.

In FIG. 11, an NFT includes two crescent-shaped base portions 1504, 1505separated by a gap. The base portions 1504, 1505 have a crescent shapein this example, although other shapes may be used, e.g. a stadium,rectangle or other topographically equivalent shapes, designed toenhance the coupling of light from the waveguide (not shown) to thesurface plasmon. The peg 1506 has a flared end 1506 a that extendstowards the gap between the base portions 1504, 1505. The peg 1506 andbase portions 1504, 1505 are not joined directly together. The flaredend 1506 a is a geometrical structure that improves plasmonic couplingbetween the rod 1506 and base portion 1504. A first heat sink 1508 joinsthe peg 1506 to the write pole 902, and second heat sink 1509 joins thebase portions 1504, 1505 to the write pole 902. The heat sinks 1508,1509 have oval and round shapes in this example, although other shapesmay be used. For the shape of heat sink 1509 may follows that of thebase portions 1504, 1505.

In FIG. 12, an NFT includes a circular disc-shaped base portion 1604 anda peg 1606. The peg 1606 is rod-shaped and extends to a middle of thebase portion 1604. The base portion 1604 is has two, concentric sections1604 a-b that are formed of different materials. The sections 1604 a-bmay be configured to improve any combination of plasmon coupling, heatsinking, adhesion, and diffusion prevention. For example, section 1604 amay be formed from a thermally robust material that adheres well to thepeg 1606, and section 1604 b may be formed from a plasmonic materialchosen for efficient plasmonic excitation and coupling. A stadium shapemay instead be used for the outer contours of the base portion 1604, aswell as the contours of the sections 1604 a-b. A heat sink 1608 has acontour that follows that of the base portion 1604 and extends from amajor surface of the inner section 1604 a of the base portion 1604 tothe write pole 902. The heat sink 1608 may be the same size as the outercontours of the base portion 1604 in some embodiments. A lower baseportion 1610 may optionally be used. The lower base portion 1610 maycover one or both sections 1604 a-b of the base portion 1610.

In FIG. 13, an NFT includes a circular disc-shaped base portion 1704 anda peg 1706. The peg 1706 has a flared end 1706 a that extends into acenter of the base portion 1704. The flared end 1706 a is a geometricalstructure that may improve adhesion and/or thermal transport and/orplasmonic coupling between the peg 1706 and base portion 1704. The baseportion 1704 is has two, concentric sections 1704 a-b that are formed ofdifferent materials, and may be configured to improve any combination ofplasmon coupling, heat sinking, adhesion, and diffusion prevention. Astadium shape may instead be used for the outer contours of the baseportion 1704, as well as the contours of the sections 1704 a-b. A heatsink 1708 has a contour that follows that of the base portion 1704 andextends from a major surface of the inner section 1704 a of the baseportion 1704 to the write pole 902. The heat sink 1708 may be the samesize as the outer contours of the base portion 1704 in some embodiments.A lower base portion 1710 may optionally be used similar to the lowerbase portion 910 in the description of FIG. 5. The lower base portion1710 may cover one or both sections 1704 a-b of the base portion 1710.In FIG. 14, an NFT includes multiple base portions 1803-1805 and a peg1806. The base portions include a disc 1805 (shown circular, but may bestadium-shaped) and two crescent shaped portions 1803, 1804 (showncrescent but may take other shapes) that are not directly connected toeither the disc 1805 or the peg 1806. The peg 1806 has a flared end 1806a that extends into a center of the disc-shaped base portion 1805. Aheat sink 1808 has a contour that follows that of the base portion 1805and extends from a major surface of the base portion 1804 to the writepole 902. The heat sink 1808 may be the same size as the outer contoursof the base portion 1804 in some embodiments. Optionally, one or both ofthe crescent shaped portions can be connected to the heat sink 1808. Alower base portion 1810 may optionally be used similar to the lower baseportion 910 in the description of FIG. 5. The lower base portion 1810may cover one or both sections of the base portion 1810.

In FIG. 15, an NFT includes a disc-style base portion 1904 and a peg1906. The peg 1906 is rod-shaped and abuts an edge of the base portion1904. The base portion 1904 has a circular contour in this example,although a stadium shape may also be used. A heat sink 1908 extends froma major surface of the base portion 1904 to the write pole 902 and maybe configured as described in regards to FIG. 5. A lower base portion1910 may optionally be used as described in regards to FIG. 5.

In FIG. 16, an NFT includes a disc-style base portion 2004 and a peg2006. The peg 2006 is rod-shaped and extends partially into the baseportion 2004, e.g., between the center of the base portion 2004 and anedge of the base portion 2004 that faces the recording media. The baseportion 2004 has a circular contour in this example, although a stadiumshape may also be used. A heat sink 2008 extends from a major surface ofthe base portion 2004 to the write pole 902 and may be configured as thedescription of FIG. 5. A lower base portion 2010 may optionally be usedas in the description of FIG. 5. The overlap between the peg and thebase portion as shown, e.g., in FIGS. 5, 14, and 16 may be chosen tooptimize the efficiency, areal density capability and/or reliability ofthe device. The embodiments of FIGS. 15 and 16 (as well as others) inparticular may gain advantage by having the peg made of a thermallyrobust material and the disc made of a plasmonic material.

Any of the embodiments described above, or combinations of any of theembodiments above may use any combination of disclosed thermally robustmaterial for the peg and disclosed plasmonic material for the otherstructures (e.g., NFT base portions or discs). Also, combinations ofdisclosed material may be used in individual components, e.g., layers ofdifferent thermally robust materials may form the peg, layers ofplasmonic and thermally robust materials may form the peg and/or other(non-peg) parts of the NFT (e.g., the disc or one or more of amulti-layer disc), and layers of different plasmonic materials may beused to form the other (non-peg) parts of the NFT.

In some embodiments, the relationship between the optical properties ofthe peg material and disc material may be selected to ensure that thesize of the optical spot is of a desired size. The optical properties ofthe peg and disc materials can be described by their “relativepermittivity”, ε. Where ϑ is a material dependent, complex, opticalfrequency (ω) dependent quantity of the form ε(ω)=ε_(r)(ω)+iε_(i)(ω)that is related to the material refractive index: ε_(r)(ω)=n(ω)2−k(ω)2,ε(ω)=2*n(ω)*k(ω). The real part of the permittivity, ε_(r)(ω), describesthe electric field distribution in the material, and the imaginary part,ε_(i)(ω), describes the amount of energy lost to heating. To excite aplasmon resonance on the disc at a particular incident laser wavelength,either (1) the size and shape of the disc can be chosen to support theresonance, and ε_(r)(ω) of the disc is less than zero; or (2) theε_(r)(ω) of the material is chosen such that the given size and shapesupports a resonance.

Configurations, including size and shape, relative position, materialsor combinations thereof in disclosed embodiments can be chosen such that(1) the disc converts incident photons into plasmons; (2) the plasmonsare coupled from the disc to the peg; (3) the peg couples energy intothe magnetic storage medium. “Disc” as used herein does not imply anyprescribed shape or configuration but instead a unit or portion of theNFT that converts energy from photons to plasmons. The disc may includeone or more than one pieces. The disc may include more than one piece,more than one material, or both.

The disc may either be in direct contact with the peg where theinterface is abutted, overlapping or stitched to the peg, is separatedfrom the peg by some distance, or the more than one piece of the peg maybe separated by some distance. The peg may be a rod like structure or itmay contain geometrical structures that improve adhesion, plasmoniccoupling, or both. The amount of overlap between the peg and the disc,if present may be chosen to advantageously affect efficiency, arealdensity capability, reliability, or any combination thereof. Excessive,undesirable heating may be prevented or minimized by heat sinking thedisc, the peg, or both using one or more heat sink units. The one ormore heat sink units may be made of the same or a different materialthan the peg, the disc or both.

In some embodiments, the imaginary part of the permittivity (ε_(i)(ω))of all materials (peg and disc for example) utilized are kept as smallas possible in order to reduce the amount of heating in the device dueto plasmon resonance. In some embodiments, the imaginary part of thepermittivity could be higher if the thermal, mechanical, or bothstabilities were increased to at least partially offset the increase intemperature. In some embodiments the imaginary part of the permittivitycan be large so long as the absolute magnitude of the permittivity islarge, so as to reduce the total internal field and minimize heating.

In some embodiments, materials of the peg and the disc can be chosenbased at least in part, on the real part of the permittivity (ε_(r)(ω)of the materials. For the peg to be able to focus the field into themedium, the real part of the permittivity of the peg material must beapproximately equal to, or less than the real part of the permittivityof the disc at the same wavelength. In some embodiments, this impliesthat the material of the peg has a higher effective carrierconcentration than the disc. In some embodiments, the optical criteriafor the relationship between the real part of the permittivity of thepeg and the disc may be relaxed, for example if there were substantialbenefits with respect to reliability. This may be applicable, forexample in cases where a potential peg material has a relatively highmelting point, a relatively high resistance to oxidation, or both.

The impact of the real and imaginary parts of the permittivity of thepeg on the temperature of the peg, cross track erasure (which is relatedto the size of the optical spot on the magnetic media), or both can beevaluated. FIGS. 17A and 17B show the effect of the real (ε_(r)(ω)) andimaginary (ε_(i)(ω)) parts of the permittivity of the peg on the pegtemperature (FIG. 17A); and cross track erasure (FIG. 17B) assuming adisc that is made of gold (Au). From FIG. 17A, it can be seen that inthis configuration, if the peg is made of a material that has a lowereffective carrier density than gold (a real permittivity greater than−30), then the temperature of the peg increases (see temperaturegradient lines on graph) rapidly as it becomes more difficult to coupleenergy into the media and the track width becomes larger (FIG. 17B). Ifthe peg is made of a material that has a higher effective carrierdensity than gold (a real permittivity less than −30) then the pegtemperature is reduced (FIG. 17A) and it becomes easier to couple energyinto the disc and the track width becomes narrower (FIG. 17B).

In some embodiments, materials for the peg, the disc, the heat sink,other portions of the NFT, or any combinations thereof can includealuminum (Al), antimony (Sb), bismuth (Bi), chromium (Cr), cobalt (Co),copper (Cu), erbium (Er), gadolinium (Gd), gallium (Ga), gold (Au),hafnium (Hf), indium (In), iridium (Ir), iron (Fe), manganese (Mn),molybdenum (Mo), nickel (Ni), niobium (Nb), osmium (Os), palladium (Pd),platinum (Pt), rhenium (Re), rhodium (Rh), ruthenium (Ru), scandium(Sc), silicon (Si), silver (Ag), tantalum (Ta), tin (Sn), titanium (Ti),vanadium (V), tungsten (W), ytterbium (Yb), yttrium (Y), zirconium (Zr),or combinations thereof. Illustrative examples of materials for the peg,the disc, the heat sink, or any combinations thereof can include binaryand/or ternary alloys including Al, Sb, Bi, Cr, Co, Cu, Er, Gd, Ga, Au,Hf, In, Ir, Fe, Mn, Mo, Ni, Nb, Os, Pd, Pt, Re, Rh, Ru, Sc, Si, Ag, Ta,Sn, Ti, V, W, Yb, Y, Zr, or combinations thereof. Illustrative examplesof materials for the peg, the disc, the heat sink, or any combinationsthereof can include lanthanides, actinides, or combinations thereofincluding Al, Sb, Bi, Cr, Co, Cu, Er, Gd, Ga, Au, Hf, In, Ir, Fe, Mn,Mo, Ni, Nb, Os, Pd, Pt, Re, Rh, Ru, Sc, Si, Ag, Ta, Sn, Ti, V, W, Yb, Y,Zr, or combinations thereof. Illustrative examples of materials for thepeg, the disc, the heat sink, or any combinations thereof can includedispersions including Al, Sb, Bi, Cr, Co, Cu, Er, Gd, Ga, Au, Hf, In,Ir, Fe, Mn, Mo, Ni, Nb, Os, Pd, Pt, Re, Rh, Ru, Sc, Si, Ag, Ta, Sn, Ti,V, W, Yb, Y, Zr, or combinations thereof. Illustrative examples ofmaterials for the peg, the disc, the heat sink, or any combinationsthereof can include alloys or intermetallics based on or including Al,Sb, Bi, Cr, Co, Cu, Er, Gd, Ga, Au, Hf, In, Ir, Fe, Mn, Mo, Ni, Nb, Os,Pd, Pt, Re, Rh, Ru, Sc, Si, Ag, Ta, Sn, Ti, V, W, Yb, Y, Zr, orcombinations thereof. Illustrative alloys or intermetallics can include,for example binary and ternary silicides, nitrides, and carbides. Forexample vanadium silicide (VSi), niobium silicide (NbSi), tantalumsilicide (TaSi), titanium silicide (TiSi), palladium silicide (PdSi) forexample zirconium nitride (ZrN), aluminum nitride (AlN), tantalumnitride (TaN), hafnium nitride (HfN), titanium nitride (TiN), boronnitride (BN), niobium nitride (NbN), or combinations thereof.Illustrative carbides can include, for example silicon carbide (SiC),aluminum carbide (AlC), boron carbide (BC), zirconium carbide (ZrC),tungsten carbide (WC), titanium carbide (TiC) niobium carbide (NbC), orcombinations thereof. Additionally doped oxides can also be utilized.Illustrative doped oxides can include aluminum oxide (AlO), siliconoxide (SiO), titanium oxide (TiO), tantalum oxide (TaO), yttrium oxide(YO), niobium oxide (NbO), cerium oxide (CeO), copper oxide (CuO), tinoxide (SnO), zirconium oxide (ZrO) or combinations thereof. Illustrativeexamples of materials for the peg, the disc, the heat sink, or anycombinations thereof can include conducting oxides, conducting nitridesor combinations thereof of various stoichiometries where one part of theoxide, nitride or carbide includes Al, Sb, Bi, Cr, Co, Cu, Er, Gd, Ga,Au, Hf, In, Ir, Fe, Mn, Mo, Ni, Nb, Os, Pd, Pt, Re, Rh, Ru, Sc, Si, Ag,Ta, Sn, Ti, V, W, Yb, Y, Zr, or combinations thereof. Illustrativeexamples of materials for the peg, the disc, the heat sink, or anycombinations thereof can include a metal including Al, Sb, Bi, Cr, Co,Cu, Er, Gd, Ga, Au, Hf, In, Ir, Fe, Mn, Mo, Ni, Nb, Os, Pd, Pt, Re, Rh,Ru, Sc, Si, Ag, Ta, Sn, Ti, V, W, Yb, Y, Zr doped with oxide, carbide ornitride nanoparticles. Illustrative oxide nanoparticles can include, forexample, oxides of yttrium (Y), lanthanum (La), barium (Ba), strontium(Sr), erbium (Er), zirconium (Zr), hafnium (Hf), germanium (Ge), silicon(Si), calcium (Ca), aluminum (Al), magnesium (Mg), titanium (Ti), cerium(Ce), tantalum (Ta), tungsten (W), thorium (Th), or combinationsthereof. Illustrative nitride nanoparticles can include, for example,nitrides of zirconium (Zr), titanium (Ti), tantalum (Ta), aluminum (Al),boron (B), niobium (Nb), silicon (Si), indium (In), iron (Fe), copper(Cu), tungsten (W), or combinations thereof. Illustrative carbidenanoparticles can include, for example carbides of silicon (Si),aluminum (Al), boron (B), zirconium (Zr), tungsten (W), titanium (Ti),niobium (Nb), or combinations thereof. In some embodiments nanoparticlescan include combinations of oxides, nitrides, or carbides. It is to beunderstood that lists of combinations of elements are not exclusive tomonoatomic binary combinations, for example VSi is taken to include V₂Siand VSi₂, for example.

The real and imaginary permittivity of an element, alloy, or compositioncan be determined using methods such as spectroscopic ellipsometry orimplied from spectroscopic reflectivity and transmissivity measurementsof films of representative thickness. The real and imaginarypermittivity of many common materials can be garnered from scientificreports or collations thereof, in some cases a conversion between therefractive index and the permittivity must be completed (the complexpermittivity is the square of the complex refractive index ε=(n+ik)²).For example the permittivity of Au at a wavelength of 830 nm can bedetermined from the refractive index data compiled in the “Handbook ofOptical Constants of Solids” (Ed. Edward D. Palik, Academic Press 1985),the disclosure of which is incorporated herein by reference thereto,where the value given is at a wavelength of 826.6 nm and the complexrefractive index is (0.188+5.39i). The complex permittivity is then(0.188+5.39i)² or (−29.0+2.0i).

TABLE 1 Refractive indices and permittivities from “Handbook of OpticalConstants of Solids” (Ed. Edward D. Palik, Academic Press 1985)Wavelength Refractive Index Permittivity Material (nm) n k RealImaginary Absolute Au 826.6 0.188 5.39 −29.0 2.0 29.1 Ni 826.6 2.53 4.47−13.6 22.6 26.4 Al 826.6 2.74 8.31 −61.5 45.5 76.6 Ag 826.6 0.145 5.5−30.2 1.6 30.3 Cu 826.6 0.26 5.26 −27.6 2.7 27.7 Ir 826.6 2.65 5.39−22.0 28.6 36.1 Rh 826.6 2.78 6.97 −40.9 38.8 56.3 Pt 826.6 2.92 5.07−17.2 29.6 34.2 Os 826.5 2.84 1.8 4.8 10.2 11.3

In some embodiments, a disc can be made of one of the illustrativematerials discussed above having a first real permittivity (ε_(r)(ω)¹)and a peg can be made of one of the illustrative materials discussedabove that has a second real permittivity ((ε_(r)(ω)²) where the secondreal permittivity ((ε_(r)(ω)²) is not greater than (or is less than orequal to) the first real permittivity (ε_(r)(ω)¹). In some embodiments,a peg can be made of a material having a real permittivity (ε_(r)(ω)²)that is not greater than (or is less than or equal to) −30 for exampleAg, Rh, Al, Ir.

In some embodiments, a disc can be made of Cu, Ag, Al, AlTi, ZrN, TiN,Ta and a peg can be made of Au, Ag, Cu, ZrN, Ta, AlTi, Pd, Pt, Ni, Co,Ir, Rh, Al, alloys thereof, or combinations thereof, with the caveatthat the disc and the peg are not made of the same material. In someembodiments, the disc does not include gold or any alloy or materialincluding gold. In some embodiments, a peg can be made of Rh, Al, Ir,Ag, Cu, Pd, Pt, alloys thereof, or combinations thereof. In someembodiments, a peg can include Rh or Ir. In some embodiments a peg caninclude Rh. In some embodiments a peg can be made of an Au, Rh, Irternary alloy or a Rh, Ir, Pd ternary alloy. In some embodiments a pegcan be made of an intermetallic containing one of Rh or Ir and one of Tior Zr or Hf or V or Nb or Ta

In some embodiments, materials that have a real permittivity less than−10 (at a wavelength of 830 nm) can be used as a peg material. In someembodiments, materials with either (exclusively either) low imaginarypermittivity, or very large absolute real and very large absoluteimaginary permittivity can be utilized for the peg material. In the caseof low imaginary permittivity, imaginary permittivity may be traded formechanical robustness. For example, silver has imaginary permittivity<1, indicating very low loss, but is not mechanically or thermallyrobust, nor resistant to corrosion, whereas ZrN and Ta are mechanicallyrobust and have imaginary permittivity less than 15. Materials withlarge absolute real permittivity and large imaginary permittivity mayalso be advantageous as peg materials as they suffer less from heating.Illustrative examples can include Al, Rh, NiFe, AlTi and Ir. In someembodiments, materials that are hard, mechanically robust, resistant tooxidation, have high melting temperature, large absolute permittivity,or combinations thereof may be utilized. Illustrative examples caninclude Rh and Ir.

In some embodiments, a disc can be made of one of the illustrativematerials discussed above having a first real permittivity (ε_(r)(ω)¹)and a peg can be made of one of the illustrative materials discussedabove that has a second real permittivity ((ε_(r)(ω)²) where the secondreal permittivity ((ε_(r)(ω)²) is not greater than and within 50% of thefirst real permittivity (ε_(r)(ω)¹). In some embodiments the material ofthe peg also has a relatively high thermal stability and resistance tooxidation. In some embodiments the material of the peg also has arelatively high thermal stability and resistance to oxidation, forexample Rh or Ir but not Ni

In some embodiments, a disc can be made of one of the illustrativematerials discussed above and a peg can be made of a material having arelatively high melting point. In some illustrative embodiments,materials with high melting points can include those having a meltingpoint of not less than (or even greater than or equal to) 1000° C. Insome illustrative embodiments, materials with high melting points caninclude those having a melting point of not less than (or even greaterthan or equal to) 1500° C. In some illustrative embodiments, materialswith high melting points can include those having a melting point of notless than (or even greater than or equal to) 1800° C. Illustrativematerials that are considered to have relatively high melting points caninclude, for example those in Table 2 below.

TABLE 2 Element Melting point (° C.) Be 1278 B 2300 C 3550 Si 1410 Sc1539 Ti 1660 V 1890 Cr 1857 Mn 1244 Fe 1535 Co 1495 Ni 1453 Y 1523 Zr1852 Nb 2408 Mo 2617 Tc 2172 Ru 2310 Rh 1966 Pd 1552 Nd 1010 Pm 1080 Sm1072 Gd 1311 Tb 1360 Dy 1409 Ho 1470 Er 1522 Tm 1545 Lu 1659 Hf 2227 Ta2996 W 3410 Re 3180 Os 3045 Ir 2410 Pt 1772 Au 1064 Th 1750 Cm 1340 Ac1050 Pa 1600

In some embodiments, disclosed NFTs including a disc and a peg made ofdifferent materials can also include optional adhesion layers. In someembodiments, the optional adhesion layers can be adjacent one or moresurfaces of the peg. Experimental evidence has shown, with respect torhodium pegs in particular, that the rhodium often gets oxidized duringprocessing and/or formation of the peg itself. An overlying adhesionlayer would be advantageous both to maintain the peg in the desiredlocation (prevent recession via the adhesive properties of the adhesionlayer) and protect the material of the peg (e.g., rhodium) fromoxidation during further processing. In some embodiments, the adhesionlayer could entirely wrap one or more portions of the NFT or peg portionof the NFT. In some embodiments, the adhesion layer could wrap less thanthe entire NFT or peg portion.

Possible materials for an adhesion layer can be chosen based at least inpart on the ability of the material to maintain a bond with the pegmaterial, the ability of the material to maintain a bond with theadjacent material, or combinations thereof. Typically, the NFT or morespecifically the peg, is surrounded by an oxide, therefore in order todetermine the ability of a potential material to maintain a bond withthe adjacent material, the bond strength of an element (for example)with oxygen (O) can be utilized. Table 3 below shows the bond strengthto Rhodium (Rh) as an example, the bond strength to oxygen (O), theoxidation free energy and a figure of merit (FOM) based on these threeconsiderations for various elements. It should be noted thatillustrative materials for adhesion layers for use in pegs that are madeof materials other than Rh could be chosen, based at least in part, onsimilar considerations by considering the bond strength of the potentialelements to the peg material (instead of the bond strength to Rh as seenin Table 3). Generally, an element with a bond strength to Rh that is atleast the same as Rh to Rh, a bond strength to O that is at least thesame as the bond strength of Rh to O, or some combination thereof may beuseful. Higher FOMs indicate that the element may be advantageous.

TABLE 3 Bond Strength Oxidation Bond Strength to Rh Free to O (kJ/molEnergy (kJ/mol Element at 298°) (kJ/mol) at 298°) FOM Au 232 223 −1 B475 −750 809 4 Ba 259 −1050 562 1 C 580 −400 1076 6 Ce 545 790 5 Eu 238473 0 H 241 −350 430 0 La 550 798 5 O 405 498 2 P 353 589 2 Rh 235 −500405 0 Sc 444 −1100 671 3 Si 395 −800 800 4 Th 513 877 5 Ti 390 −900 6664 U 519 755 4 V 364 −800 637 3 Y 446 −1100 714 4

Based at least in part on the above considerations, useful materials foradhesion layers may include boron (B), carbon (C), cerium (Ce),lanthanum (La), phosphorus (P), scandium (Sc), silicon (Si), thorium(Th), titanium (Ti), uranium (U), vanadium (V), yttrium (Y), orcombinations thereof. In some embodiments, adhesion layers can includeyttrium (Y), carbon (C), or combinations thereof.

Disclosed adhesion layers can be located on one or more surfaces of thepeg, the disc, or both. In some embodiments, an optional adhesion layercan be located on at least one surface of the peg. In some embodiments,an adhesion layer or layers can be located on at least one or moresurfaces of the peg that are adjacent an oxide or oxide containingstructure. An example of an oxide containing structure that may be nextto the peg includes cladding layers. As such, in some embodiments, anadhesion layer or layers can be located on at least one or more surfacesof the peg that are adjacent one or more cladding layers or structures.

FIG. 18A shows an illustrative embodiment depicting a possible locationfor an optional adhesion layer. FIG. 18A includes a disc 10, which doesnot necessarily have to be oval in shape, a peg 12 and an adhesion layer15. It should also be noted that FIG. 18A illustrates the delineationbetween the rod 11 and the peg, the portion of the rod 11 which is infront of or not within the disc 10 (this construct applies to allembodiments depicted herein, whether stated or not). Stated another way,the rod 11 includes the peg 12, but the peg 12 does not include theentire rod 11, except in cases where the peg is abutted to the rod andthen the peg also includes the entire rod. The embodiment of the devicein FIG. 18A includes an adhesion layer 15 that is located around,adjacent to, or on the entire rod 11. Although not depicted in FIG. 18A,because it is a plan view, the adhesion layer 15 can also be locatedunderneath and on top of the rod 11. Stated another way, the adhesionlayer 15 in such an embodiment can cover all surfaces of the rod 11,except the air bearing surface (ABS) 9. Such an embodiment can be formedby depositing the material of the adhesion layer before the rod materialis deposited (e.g., as a seed layer for example), depositing and formingthe rod and then depositing the material of the adhesion layer on thesurfaces of the rod 11 as seen in FIG. 18A as well as on the top surfaceof the rod, before any additional cladding material is deposited aroundor on the rod. Such all-around adhesion layers may help adhere the pegto the adjacent dielectrics and can prevent or at least minimizediffusion of the peg material into the disc or disc material into thepeg.

FIG. 18B illustrates another example of a device including an optionaladhesion layer. FIG. 18B includes a disc 10, which does not necessarilyhave to be oval in shape, a peg 12 and an adhesion layer 16. Theadhesion layer 16 in this embodiment is located around, adjacent to, oron the peg 12, but no portion of the remainder of the rod. Although notdepicted in FIG. 18B, because it is a plan view, the adhesion layer 16can also be located underneath and on top of the peg 12. Stated anotherway, the adhesion layer 16 in such an embodiment can cover all surfacesof the peg 12, except the air bearing surface (ABS). Such an embodimentcan be formed by depositing the material of the adhesion layer beforethe peg material is deposited (e.g., as a seed layer for example),forming the peg and then depositing the material of the adhesion layerafter formation of the peg (and in some embodiments part of the disc,e.g., the bottom disc) as well as on the top surface of the peg, beforeany additional cladding material is deposited around or on the peg. Suchconfigurations may promote adhesion between the peg and the dielectricwithout disrupting the thermal pathway between the rod and disc.

FIG. 18C illustrates another example of a device including an optionaladhesion layer. FIG. 18C includes a disc 10, which does not necessarilyhave to be oval in shape, a peg 12 and an adhesion layer 17. Theadhesion layer 17 in this embodiment is only located at the air bearingsurface (ABS) of the peg, which can also be called the front of the peg12. This type of an adhesion layer can also be referred to as an ABScap. This adhesion layer could then optionally be further covered orhave deposited thereon an overcoat layer. This configuration may havethe advantage of promoting adhesion of the peg to the air bearingsurface.

FIG. 18D illustrates another example of a device including an optionaladhesion layer. FIG. 18D includes a disc 19, which although not visiblein FIG. 18D is a two layer disc including a bottom disc and a top disc.This is shown in FIG. 18E, which shows the disc 19 made up of a bottomdisc 20 and a top disc 21, delineated by the dashed line. The bottomdisc 20 has a larger footprint than does the top disc 21 and the topdisc 21 is located entirely within the footprint of the bottom disc 20.The adhesion layer 18 in this illustrated embodiment is located on theexposed outer surface of the bottom disc 20, where the top disc 21 isnot covering the bottom disc 20. The adhesion layer 18 is illustrated inthis embodiment as also covering the sides of the top disc 21. It shouldbe noted that this portion of the adhesion layer 18 is not necessary andneed not be present. Although not depicted in this embodiment, theadhesion layer may also be located underneath the bottom disc 20, e.g.,adjacent the bottom surface 22 of the bottom disc 20 (as seen in FIG.18E). It should also be noted that the illustrated adhesion layer 18 islocated adjacent the side surfaces of the peg 12. Such an adhesion layercan be formed by first depositing the material of the adhesion layer (ifit is desired to have the adhesion layer adjacent the bottom surface 22of the bottom disc 20), then depositing and forming the bottom disc,depositing the top disc and then depositing the material of the adhesionlayer 18. Adhesion layers such as these may be able to prevent or atleast minimize diffusion associated with disc materials that aren'tcompletely dense. In some alternative embodiments, an adhesion layer mayalternatively or optionally be located between the bottom disc 20 andthe top disc 19. An adhesion layer located between the two discs mayserve to limit the volume of under-dense material thereby limiting thesize of the holes that may appear upon densification.

Portions of the adhesion layer that may be functioning as a seed layeras well, e.g., will have materials deposited thereof may, but need notbe made of materials different than the remaining adhesion layermaterials. It should also be noted that any combinations of the abovediscussed adhesion layer configurations or portions thereof can also beutilized and are considered to have been disclosed herein.

In reference now to FIG. 19A, shows an ABS view of an NFT geometry inaccordance with embodiments described herein. The NFT 112 is disposed ata media-facing surface 108 according to an example embodiment. Thex-axis in this figure is aligned in a cross-track direction, and thez-axis is aligned in a down-track direction. The aperture 1922 is shownproximate an extension of the write pole 1916. The plasmonic materialportion 1920 forms a top wall that separates the aperture 1922 from thewrite pole 1916. Side portions 1902, 1903 of plasmonic material formside walls surround the aperture 1922 in the cross-track direction.Plasmonic portion 1921 forms a bottom wall of the aperture 1922. Thesewalls are generally parallel to the media-facing surface. Turning now toFIG. 19B, The dashed line represents the media facing surface, the wallsin this figure are normal to the media facing surface. Turning now toFIG. 19C, In general, optical fields are directed from a waveguide onthe right of 19C toward the ABS (dashed line, 19C) and surface plasmonresonance causes surface plasmons to be directed in this normaldirection to a recording media. FIG. 19B shows a top-down view of thedevice described in FIG. 19A and FIG. 19C illustrates a cross-sectionview. The NFT shown in FIGS. 19A-19C will be referred to herein as an“aperture” NFT. According to various implementations, an aperture NFThas more than one notch. FIGS. 19D and 19E illustrate an NFT having anaperture 1950 with two notches 1925, 1926.

In FIG. 20, a cross-sectional, perspective view shows details of an NFT2012 according to an example embodiment. The cross section is takenalong a downtrack centerline of a recording head. The NFT 2012 includesa closed aperture 2022 and a notch 2023 protruding therein. A waveguide2040 delivers energy to the NFT 2012. Omitted in this view is a fillermaterial (e.g., dielectric) in the aperture 2022.

FIGS. 21A-21C illustrates an NFT according to an example embodiment. Inthis example, all or a portion of the notch 2115 comprises one or moremechanically robust materials. The aperture 2110 and the walls 2125comprise a material different from the material of the notch. FIG. 21Aillustrates a ABS view. FIG. 21B shows a top-down view and FIG. 21Cillustrates a cross section. The dotted line 2135 in FIGS. 21A and 21Brepresents the ABS side.

FIGS. 22A-22C illustrates an NFT according to various embodiments. Inthis example, all or a portion of the notch 2215 and the aperture arecoated with a coating 2245 comprising one or more mechanically robustmaterials. The aperture 2210, the notch 2215, and the walls 2225comprise a material different from the material of the coating 2245.FIG. 22A illustrates an ABS view. FIG. 22B shows a top-down view andFIG. 22C illustrates a cross section view. While FIGS. 22A-22Cillustrate an example in which the notch 2215 and the aperture 2210 arecoated with the coating 2245, it is to be understood that only theaperture 2210 or the notch 2215 may be coated with the coating 2245 insome cases. The dotted line 2235 in FIGS. 22A and 22B represents the ABSside.

FIGS. 23A-23C illustrates an NFT according to various embodiments. Inthis example, a first portion 2317 of the notch 2315 closest to the ABScomprises one or more mechanically robust materials. The first portion2317 is shown in FIGS. 23B and 23C and is proximate the ABS 2335. Asecond portion 2319 of the notch 2315 further from the ABS comprises amaterial different from the material of the first portion 2317. Theaperture 2310 and the walls 2325 comprise a material different from atleast the first portion 2317 of the notch 2315.

FIGS. 24A-24C illustrates an NFT according to various embodiments. Inthis example, all or a portion of the notch 2415 comprises one or moremechanically robust materials. A portion of the notch 2415 is coatedwith a coating 2455. According to various implementations, the coating2455 comprises the same or similar material as that of the walls 2425.For example, the coating 2455 and the walls 2425 comprise Au. In somecases, the coating 2455 is disposed on the notch except for the one orboth of the waveguide-facing surface 2460 and the ABS 2435. As shown inthe top-down view of FIG. 24B and the cross-section view of FIG. 24C,the coating is disposed on the notch 2415 except for both of thewaveguide-facing surface 2460 and the ABS 2435, According to variousconfigurations, a thickness of the coating is in a range of about 5 nmto 20 nm. According to various configurations, the notch 2415 comprisesa different material than that of the walls 2425 and/or the aperture2410.

FIGS. 25A-25C illustrates an NFT according to various embodiments. Inthis example, all or a portion of the notch 2515 is coated with acoating 2545. According to various embodiments, the walls 2525 comprisethe same or similar material to that of the notch 2515. The coating 2545provides a barrier layer between the notch 2515 and the walls 2525. Insome cases, the material of the aperture 2510 comprises a differentmaterial from that of the notch 2515, the walls 2525, and/or the coating2545. According to various configurations, a thickness of the coating isin a range of about 0.5 nm to 20 nm. In some configurations, a thicknessof the coating is in the range of about 5 nm to 10 nm. FIG. 25Billustrates an top-down view and FIG. 25C illustrates a cross sectionview The dotted line 2535 in FIGS. 25B and 25C represents the ABS side.

FIGS. 26A and 26B show another NFT geometry. In some instances, theoptical delivery path of a HAMR slider may be optically coupled to aplanar plasmon antenna NFT 2660 also called a planar plasmon generator(PPG). The planar plasmon antenna 2660 is not only located adjacent to acore of the waveguide 2640 but also can be located adjacent the ABS2655. The energy source, (e.g., the laser diode) can be used to direct abeam of optical radiation to adjacent the planar plasmon antenna 2660via the waveguide. The planar plasmon antenna 2660 acts as an opticalantenna and is formed of plasmonic metals such as gold, silver, copper,aluminum, etc., and alloys thereof. As a result of the optical deliverypath, an optical mode of incident radiation couples to a propagatingedge plasmon mode in the planar plasmon antenna. As a result of thepropagating edge plasmon mode, optical energy is converted into plasmonenergy, which travels along the planar plasmon antenna. The planarplasmon antenna shapes and transmits the energy to a small region on themedium. As a result of the application of energy, a high temperaturerise in a small region on the media, with the region exceeding the Curietemperature having dimensions less than 100 nm occurs. This also resultsin high temperature rise in the slider near the planar plasmon antennadue to optical losses in the delivery path.

FIG. 26A illustrates a slider having a PPG NFT 2660 that includes anenlarged region 2625 and a peg region 2610 proximate the ABS 2655. Theenlarged region 2625 may be referred to herein as the NFT body.According to various implementations, at least a portion of the PPG NFT2660 comprises a mechanically robust material. For example, all or aportion of the peg region 2610 may comprise a mechanically robustmaterial. According to various embodiments, the peg region 2610 and theenlarged region 2625 comprise different materials. In some cases, thepeg 2610 comprises an oxidation resistant barrier layer (not shown) thatcoats all or a portion of the peg region 2610. The enlarged region 2625has a slope 2670 on a side of the enlarged region 2625 that faces theABS 2655. A dielectric spacer 2615 may be disposed between the pegregion 2610 and a magnetic pole 2635. In some cases, the dielectricspacer is additionally or alternatively disposed between at least aportion of the enlarged region 2625 and the magnetic pole 2635.Optionally, a diffusion barrier 2650 is disposed between at least aportion of the enlarged region 2625 and the magnetic pole 2635. Thediffusion barrier 2650 may be configured to prevent the mechanicallyrobust material from oxidizing. In some cases, the diffusion barrier2650 is configured to prevent the magnetic pole 2635 and the enlargedregion 2625 from interdiffusing. FIG. 26B illustrates a top-down view ofthe PPG NFT described in FIG. 26A. The PPG NFT includes an enlargedregion 2625 and a peg region 2610 and is disposed proximate a waveguidecore 2640. FIG. 26C illustrates the ABS view of the enlarged region2625, the peg region 2610 and the waveguide core 2640.

FIG. 27A illustrates a slider configuration having a PPG NFT 2760 thatincludes an enlarged region 2725 and a peg region 2710 proximate the ABS2755. According to various implementations, at least a portion of thePPG NFT 2760 comprises a mechanically robust material. For example, allor a portion of the peg region 2710 may comprise a mechanically robustmaterial. The enlarged region 2725 has a slope 2770 on a side of theenlarged region 2725 that faces the ABS 2755. A peg coupler 2780 isdisposed between the magnetic pole 2735 and the peg 2710. According tovarious implementations, the peg coupler 2780 comprises a same orsimilar material as the peg 2710. For example, the peg coupler 2780 maycomprise a mechanically robust material such as Rh or Ir. In some cases,the peg coupler 2780 comprises a plasmonic material such as Au or Ag.According to various implementations, the peg 2710 is separated from thepeg coupler 2780 by a dielectric spacer 2715 disposed between the pegregion 2710 and a magnetic pole 2735. In some cases, the dielectricspacer 2715 is additionally or alternatively disposed between at least aportion of the enlarged region 2725 and the magnetic pole 2735.Optionally, a diffusion barrier 2750 is disposed between at least aportion of the enlarged region 2725 and the magnetic pole 2735. Thediffusion barrier 2750 may be configured to prevent the mechanicallyrobust material from oxidizing. In some cases, the diffusion barrier2750 is configured to prevent the magnetic pole 2735 and the enlargedregion 2725 from interdiffusing.

FIG. 27B illustrates a slider configuration having a PPG NFT 2761 thatincludes an enlarged region 2726 and a peg region 2711 proximate the ABS2756. Similarly to FIG. 27A, at least a portion of the PPG NFT 2761comprises a mechanically robust material. For example, all or a portionof the peg region 2711 may comprise a mechanically robust material. Theenlarged region 2726 has a slope 2771 on a side of the enlarged region2726 that faces the ABS 2756. A peg coupler 2781 is disposed between themagnetic pole 2736 and the peg 2711. According to variousimplementations, the peg 2711 is separated from the peg coupler by adielectric spacer 2716 disposed between the peg region 2711 and amagnetic pole 2736. In some cases, the dielectric spacer 2716 isadditionally or alternatively disposed between at least a portion of theenlarged region 2726 and the magnetic pole 2736. A first diffusionbarrier 2791 is disposed between the peg coupler 2781 and the magneticpole 2736. According to various embodiments, the first diffusion barrier2791 is configured to prevent the magnetic pole 2736 and the peg coupler2781 from interdiffusing. Optionally, a second diffusion barrier 2751 isdisposed between at least a portion of the enlarged region 2726 and themagnetic pole 2736. In some cases, the second diffusion barrier 2751 isconfigured to prevent the magnetic pole 2736 and the enlarged region2726 from interdiffusing.

FIG. 28 illustrates a slider configuration having a PPG NFT 2860 thatincludes an enlarged region 2825 and a peg region 2810 proximate the ABS2855. According to various implementations, at least a portion of thePPG NFT 2860 comprises a mechanically robust material. For example, allor a portion of the peg region 2810 may comprise a mechanically robustmaterial. The enlarged region 2825 has a step 2870 on a side of theenlarged region 2825 that faces the ABS 2855. According to variousimplementations, the peg 2810 is separated from a magnetic pole 2835 bya dielectric spacer 2815 disposed between the peg region 2810 and amagnetic pole 2835. In some cases, the dielectric spacer 2815 isadditionally or alternatively disposed between at least a portion of theenlarged region 2825 and the magnetic pole 2835. Optionally, a diffusionbarrier 2850 is disposed between at least a portion of the enlargedregion 2825 and the magnetic pole 2835. The diffusion barrier 2850 maybe configured to prevent the mechanically robust material fromoxidizing. In some cases, the diffusion barrier 2850 is configured toprevent the magnetic pole 2835 and the enlarged region 2825 frominterdiffusing. While FIG. 28 does not show a peg coupler as describedin FIGS. 27A and 27B, it is to be understood that the system of FIG. 28may also include a peg coupler. In some cases, the system of FIG. 28also includes a diffusion barrier between the peg coupler and themagnetic pole.

While FIGS. 26A-28 show a PPG system configured for use with TMpropagating light, the system may be configured to work with TEpropagating light. In A TE system, the waveguide is in a differentlocation. FIGS. 29A-29C illustrate a PPG system for use with TEpropagating light. FIG. 29A illustrates a slider having a PPG NFT thatincludes an enlarged region 2925 and a peg region 2910 proximate the ABS2955. According to various implementations, at least a portion of thePPG NFT comprises a mechanically robust material. For example, all or aportion of the peg region 2910 may comprise a mechanically robustmaterial. According to various embodiments, the peg region 2910 and theenlarged region 2925 comprise different materials. FIG. 29B illustratesa top-down view of the PPG NFT described in FIG. 29A. The PPG NFTincludes an enlarged region 2925 and a peg region 2910 and is disposedproximate two sides of a waveguide core 2942, 2944. FIG. 29C illustratesthe ABS view of the enlarged region 2925, the peg region 2910 and thesides of the waveguide core 2942, 2944.

FIGS. 30A and 30B show another NFT geometry. This NFT 3000 is configuredas side-by-side, elongated plates 3022, 3024 (elongated in they-direction) with a gap 3026 therebetween. The plates 3022, 3024 aredisposed on the x-y plane, and the gap 3026 runs in the y-direction froman excitation location to the ABS 3008. The gap 3026 and surroundingareas may be filled with a dielectric material. The plates 3022, 3024are curved/chamfered at waveguide facing ends 3029 in order to improvecoupling with a waveguide (not shown). FIG. 30B illustrates an ABS viewof the NFT 3000. This arrangement may be referred to herein as the “gap”NFT.

In the embodiment of FIGS. 31A-31C, an inner core portion of the NFT ismade from a mechanically robust material 3102, such as Rh or Ir, that iscoated by a plasmonic material 3104. The top-down view shown in FIG. 31Aillustrates the NFT as side-by-side, elongated plates 3122, 3124 with agap 3126 therebetween. At least a portion of the plates 3122, 3124comprises the mechanically robust material. The core portion has atleast two adjacent non-parallel surfaces 3103, 3105. The outer conformallayer of plasmonic material 3104 encompasses the at least two surfaces3103, 3105 as shown in FIG. 31B. The core may be formed of anon-magnetic material 3102 of low-solubility in the plasmonic material3104. In such a case, the non-magnetic material 3102 provides the NFThigher mechanical stability than the plasmonic material 3104. FIG. 31Cillustrates a cross-section view of the gap NFT shown in FIGS. 31A and31B. The inner core portion of the NFT is comprises a mechanicallyrobust material 3102 and at least a portion of the outer layer of theNFT 3101 comprises a plasmonic material 3104. A write pole 3135 isdisposed proximate to a side of the NFT 3101 having the mechanicallyrobust material 3102. A waveguide 3140 at least partially encompassesthe plasmonic material 3104 of the NFT 3101.

In the embodiment of FIGS. 32A-32C, a top surface of the NFT is madefrom a mechanically robust material 3202 and the rest of the platesinclude a plasmonic material 3204. The top-down view shown in FIG. 32Aillustrates the NFT as side-by-side, elongated plates 3222, 3224 with agap 3226 therebetween. FIG. 32B illustrates an ABS view of the gap NFTof FIG. 32A. From the view of FIG. 32B, it can be observed that thesurface of the NFT facing the write pole 3235 comprises the mechanicallyrobust material 3202 and the bottom portion of the NFT proximate thewaveguide core 3240 comprises a plasmonic material 3204. FIG. 32Cillustrates a cross-section view of the gap NFT shown in FIGS. 32A and32B. A layer of the NFT 3201 closest to the write pole 3235 comprises amechanically robust material 3202. The mechanically robust layer 3202may have a thickness in the range of about 10 nm to 40 nm. A waveguidecore 3240 is disposed adjacent and/or directly in contact with theplasmonic material 3204 of the NFT 3201.

In the embodiment of FIGS. 33A-33C, a small corner of the NFTresponsible for confinement is made from a mechanically robust material3302 and the rest of the plates include a plasmonic material 3304. Thetop-down view shown in FIG. 33A illustrates the NFT as side-by-side,elongated plates 3322, 3324 with a gap 3326 therebetween. FIG. 33Billustrates an ABS view of the gap NFT of FIG. 33A. From the view ofFIG. 33B, it can be observed that the a corner of the NFT facing thewrite pole 3335 comprises the mechanically robust material 3302 and theremaining portion of the NFT proximate the waveguide core 3340 comprisesa plasmonic material 3304. FIG. 33C illustrates a cross-section view ofthe gap NFT shown in FIGS. 33A and 33B. The small portion of the NFTthat comprises the mechanically robust material in FIGS. 33A and 33B isnot visible in the cross-section view. A waveguide core 3340 and a writepole 3335 are disposed adjacent and/or directly in contact with the NFT3301.

In the embodiment of FIGS. 34A-34C, a small corner of the NFTresponsible for confinement may be coated with a mechanically robustmaterial 3402 and the rest of the plates include a plasmonic material3404. In some cases, the mechanically robust material 3402 potion isfabricated during fabrication of the NFT. According to some embodimentsthe mechanically robust material portion 3402 is deposited on the NFTafter fabrication of the NFT. The top-down view shown in FIG. 34Aillustrates the NFT as side-by-side, elongated plates 3422, 3424 with agap 3426 therebetween. FIG. 34B illustrates an ABS view of the gap NFTof FIG. 34A. From the view of FIG. 34B, it can be observed that a cornersurface of the NFT facing the write pole 3435 is coated with themechanically robust material 3402 and the bottom portion of the NFTproximate the waveguide core 3440 comprises a plasmonic material 3404.FIG. 34C illustrates a cross-section view of the gap NFT shown in FIGS.34A and 34B. The small portion of the NFT that comprises themechanically robust material 3402 in FIGS. 34A and 34B is located on aside of the NFT 3401 facing the write pole 3425. A waveguide core 3440is disposed adjacent to a plasmonic material 3404 portion of the NFT3401. In some cases, the waveguide core 3440 at least partiallyencompasses the NFT 3401.

FIGS. 35A-35C illustrate another type of gap NFT in accordance withembodiments described herein. Similarly to FIGS. 35A-35C, the NFT 3500is configured as side-by-side, elongated plates 3522, 3524 with atapered gap 3526 therebetween. The plates 3522, 3524 are disposed on thex-y plane, and the gap 3526 runs in the y-direction from an excitationlocation to the ABS 3508. The gap 3526 and surrounding areas may befilled with a dielectric material. The orientation of the plates 3522,3524 causes the gap 3526 to have a taper that narrows as it approachesthe ABS 3508. An electric field is concentrated along the taper as shownin FIG. 35A. FIG. 35B illustrates an ABS view of the NFT 3500 havingplates 3510, 3515. FIG. 35C illustrates a cross-section view of the gapNFT 3500 shown in FIGS. 35A and 35B. The NFT 3500 is disposed betweenthe write pole 3525 and the waveguide core 3540. The waveguide core 3540may at least partially encompass the NFT.

In the embodiment of FIGS. 36A-36C, a small corner of the NFT at the ABSresponsible for confinement is made from a mechanically robust material3602 and the rest of the plates include a plasmonic material 3604. Thetop-down view shown in FIG. 36A illustrates the NFT as side-by-side,elongated plates 3622, 3624 with a gap 3626 therebetween. At least aportion of the plates 3622, 3624 comprises the mechanically robustmaterial 3602. FIG. 36B illustrates an ABS view of the gap NFT of FIG.36A. From the view of FIG. 36B, it can be observed that the a smallcorner of the NFT proximate the write pole 3635 comprises themechanically robust material 3602 and the bottom portion of the NFTproximate the waveguide core 3640 comprises a plasmonic material 3604.FIG. 36C illustrates a cross-section view of the gap NFT shown in FIGS.36A and 36B. The small portion of the NFT that comprises themechanically robust material in FIGS. 36A and 36B is not visible in thecross-section view. A waveguide core 3640 and a write pole 3635 aredisposed adjacent to the NFT 3601. According to various implementations,the waveguide core at least partially encompasses 3640 the NFT 3601.

In the embodiment of FIGS. 37A-37C, an edge of the NFT 3701 having thehighest concentration of electric field is made from a mechanicallyrobust material 3702 and the rest of the plates include a plasmonicmaterial 3704. The top-down view shown in FIG. 37A illustrates the NFTas side-by-side, elongated plates 3722, 3724 with a gap 3726therebetween. FIG. 37B illustrates an ABS view of the gap NFT of FIG.37A. From the view of FIG. 37B, it can be observed that the surface ofthe NFT facing the write pole 3735 comprises the mechanically robustmaterial 3702 and the bottom portion of the NFT proximate the waveguidecore 3740 comprises a plasmonic material 3704. FIG. 37C illustrates across-section view of the gap NFT shown in FIGS. 37A and 37B. The smallportion of the NFT that comprises the mechanically robust material inFIGS. 37A and 37B is not visible in the cross-section view. A waveguidecore 3740 and a write pole 3735 are disposed adjacent to the NFT 3701.In some cases, the waveguide core 3740 at least partially encompassesthe NFT 3701.

In the embodiment of FIGS. 38A-38C, a small corner of the NFT at the ABSresponsible for confinement is made from a mechanically robust material3802 and the rest of the plates include a plasmonic material 3804.According to various configurations, the mechanically robust portion3802 of the NFT is fabricated after the NFT has been fabricated. In somecases, the mechanically robust portion of the NFT 3802 is fabricated atthe same time as the rest of the NFT. The top-down view shown in FIG.38A illustrates the NFT as side-by-side, elongated plates 3822, 3824with a gap 3826 therebetween. FIG. 38B illustrates an ABS view of thegap NFT of FIG. 38A. From the view of FIG. 38B, it can be observed thatthe a small corner of the NFT proximate the write pole 3835 comprisesthe mechanically robust material 3802 and the bottom portion of the NFTproximate the waveguide core 3840 comprises a plasmonic material 3804.FIG. 38C illustrates a cross-section view of the gap NFT shown in FIGS.38A and 38B. The small portion of the NFT that comprises themechanically robust material in FIGS. 38A and 38B is not visible in thecross-section view. A waveguide core 3840 and a write pole 3835 aredisposed adjacent to the NFT 3801. In some cases, the waveguide core3840 at least partially encompasses the NFT 3801.

In the embodiment of FIGS. 39A-39C, a small corner of the NFTresponsible for confinement may be coated with a mechanically robustmaterial 3902 and the rest of the plates include a plasmonic material3904. In some cases, the mechanically robust material 3902 portion isfabricated during fabrication of the NFT. According to some embodimentsthe mechanically robust material 3902 portion is deposited on the NFTafter fabrication of the NFT. The top-down view shown in FIG. 39Aillustrates the NFT as side-by-side, elongated plates 3922, 3924 with agap 3926 therebetween. FIG. 39B illustrates an ABS view of the gap NFTof FIG. 39A. From the view of FIG. 39B, it can be observed that a cornersurface of the NFT facing the write pole 3935 is coated with themechanically robust material 3902 and the bottom portion of the NFTproximate the waveguide core 3940 comprises a plasmonic material 3904.FIG. 39C illustrates a cross-section view of the gap NFT shown in FIGS.39A and 39B. The small portion of the NFT that comprises themechanically robust material 3902 in FIGS. 39A and 39B is located on aside of the NFT 3901 facing the write pole 3935. A waveguide core 3940is disposed adjacent to a plasmonic material 3904 portion of the NFT3901. In some cases, the waveguide core 3940 at least partiallyencompasses the NFT 3901.

While FIGS. 35A-39C show a gap system configured for use with TEpropagating light in a single waveguide, the system may be configured towork with TE propagating light in two waveguides. This configurationallows the magnetic pole to be more proximate to the NFT while stillusing TE light. FIGS. 40A-40C illustrate a gap NFT system for use withTE propagating light in two waveguides. In this system, the waveguide4042, 4044 is in a different location and the plates 4022, 4024 havecorresponding peg portions 4012, 4014. According to variousimplementations, the peg portions 4012, 4014 comprise a mechanicallyrobust material. The peg portions 4012, 4014 and the plates 4022, 4024may comprise different materials. FIG. 40C illustrates a cross sectionview of a system having a TE gap NFT in accordance with FIGS. 40A and40B. The system includes a magnetic pole 4035 that is disposed proximatean NFT 4008. A gap 4005 is disposed between the magnetic pole 4035 andthe NFT 4008. The NFT 4008 includes plate portions 4020 and peg portions4010. A diffusion barrier 4060 may be disposed between at least aportion of the plate portions 4020 and the magnetic pole 4035 to preventinterdiffusion between the materials of the magnetic pole 4035 and theplate portions 4020. A waveguide core 4040 is disposed proximate the NFT4008.

FIGS. 41A-41D illustrate another type of NFT in accordance withembodiments described herein. In FIG. 41A, the NFT comprises an NFT bodyor disc 4120 and a peg 4110 that extends from the disc 4120 toward theABS 4150. According to various embodiments, all or a portion of the peg4110 comprises a mechanically robust material. While, FIG. 41A shows asubstantially circular disc when viewed from the top, the disc may beany shape. For example, FIG. 41B illustrates an example in which thedisc 4122 has an elliptical shape with a peg 4112 extending toward themedia facing surface. The type of NFT described in conjunction withFIGS. 41A and 41B will herein be referred to as a “lollipop” NFT.

FIG. 41C illustrates a cross section of a slider that includes alollipop NFT. The slider includes a magnetic pole 4135 and a heat sink4160 disposed proximate the magnetic pole 4135. An NFT 4105 comprising adisc portion 4120 and a peg portion 4114 extending from the disc portion4120 toward the ABS 4154 is disposed proximate the magnetic pole 4135. Awaveguide core 4140 is disposed proximate the NFT 4105. An ABS view ofthe lollipop NFT system is shown in FIG. 41D.

FIGS. 42A and 42B illustrate an embodiment utilizing a lollipop NFT inaccordance with embodiments described herein. In FIG. 42A, the NFTcomprises an enlarged region or disc 4220 and a peg 4210 that extendsfrom the disc 4220 toward the ABS 4250. According to variousembodiments, all or a portion of the peg 4210 comprises a mechanicallyrobust material. The peg 4210 may extend into the disc 4220. Forexample, the peg 4210 may extend under the disc 4220. FIG. 42Billustrates a cross section of a slider that includes the lollipop NFTdescribed in conjunction with FIG. 42A. The slider includes a magneticpole 4235 and a heat sink 4260 disposed proximate the magnetic pole4235. An NFT 4205 comprising a disc portion 4220 and a peg portion 4210extending from the disc portion 4220 toward the ABS 4250 is disposedproximate the magnetic pole 4235. A waveguide core 4240 is disposedproximate the NFT 4205.

FIGS. 43A and 43B illustrate an embodiment utilizing a lollipop NFTaccordance with embodiments described herein. In FIG. 43A, the NFTcomprises an enlarged region or disc 4320 and a peg 4310 that extendsfrom the disc 4320 toward the ABS 4350. According to variousembodiments, all or a portion of the peg 4310 comprises a mechanicallyrobust material. The peg 4310 may extend into the disc 4320. In theembodiment of FIGS. 43A and 43B, the peg 4310 extends into a centralregion of the disc 4320. FIG. 43B illustrates a cross section of aslider that includes the lollipop NFT described in conjunction with FIG.43A. The slider includes a magnetic pole 4335 and a heat sink 4360disposed proximate the magnetic pole 4335. An NFT 4305 comprising a discportion 4320 and a peg portion 4310 extending from the disc portion 4320toward the ABS 4350 is disposed proximate the magnetic pole 4335. Awaveguide core 4340 is disposed proximate the NFT 4305.

FIGS. 44A and 44B illustrate an embodiment utilizing a lollipop NFTaccordance with embodiments described herein. In FIG. 44A, the NFTcomprises an enlarged region or disc 4420 and a peg 4410 that extendsfrom the disc 4420 toward the ABS 4450. According to variousembodiments, all or a portion of the peg 4410 comprises a mechanicallyrobust material. The peg 4410 is disposed on the disc 4420. FIG. 44Billustrates a cross section of a slider that includes the lollipop NFTdescribed in conjunction with FIG. 44A. The slider includes a magneticpole 4435 and a heat sink 4460 disposed proximate the magnetic pole4435. An NFT 4405 comprising a disc portion 4420 and a peg portion 4410extending from the disc portion 4420 toward the ABS 4450 is disposedproximate the magnetic pole 4435. A waveguide core 4440 is disposedproximate the NFT 4405.

FIGS. 45A and 45B illustrate an embodiment utilizing a lollipop NFTaccordance with embodiments described herein. In FIG. 45A, the NFTcomprises an enlarged region or disc 4520 and a peg 4510 that extendsfrom the disc 4520 toward the ABS 4550. According to variousembodiments, all or a portion of the peg 4510 comprises a mechanicallyrobust material. The peg 4510 is abutted to the disc 4520 and does notextend into the disc 4520 as described in other examples. FIG. 45Billustrates a cross section of a slider that includes the lollipop NFTdescribed in conjunction with FIG. 45A. The slider includes a magneticpole 4535 and a heat sink 4560 disposed proximate the magnetic pole4535. An NFT 4505 comprising a disc portion 4520 and a peg portion 4510extending from the disc portion 4520 toward the ABS 4550 is disposedproximate the magnetic pole 4535. A waveguide core 4540 is disposedproximate the NFT 4505.

Unless otherwise indicated, all numbers expressing feature sizes,amounts, and physical properties used in the specification and claimsare to be understood as being modified in all instances by the term“about.” Accordingly, unless indicated to the contrary, the numericalparameters set forth in the foregoing specification and attached claimsare approximations that can vary depending upon the desired propertiessought to be obtained by those skilled in the art utilizing theteachings disclosed herein. The use of numerical ranges by endpointsincludes all numbers within that range (e.g. 1 to 5 includes 1, 1.5, 2,2.75, 3, 3.80, 4, and 5) and any range within that range.

The foregoing description of the example embodiments has been presentedfor the purposes of illustration and description. It is not intended tobe exhaustive or to limit the inventive concepts to the precise formdisclosed. Many modifications and variations are possible in light ofthe above teaching. Any or all features of the disclosed embodiments canbe applied individually or in any combination are not meant to belimiting, but purely illustrative. It is intended that the scope belimited not with this detailed description, but rather determined by theclaims appended hereto.

What is claimed is:
 1. A recording head, comprising: a near fieldtransducer (NFT) comprising: a base portion; and a peg embedded in apart of the base portion that faces a media-facing surface, the pegcomprising an elongated outer part that extends from a lower edge of theenlarged portion towards the media-facing surface and an embedded partthat is embedded within the base portion, one or both of the baseportion and the peg comprising a thermally robust material; and awaveguide comprising a first core portion and a second core potion, theNFT disposed between the first waveguide core portion and the secondwaveguide core portion.
 2. The recording head of claim 1, wherein NFT isa planar plasmon generator.
 3. The recording head of claim 1, whereinthe NFT comprises a plasmonic material.
 4. The recording head of claim1, wherein the base portion and the peg comprise different materials. 5.The recording head of claim 1, wherein the peg comprises a thermallyrobust material.
 6. The recording head of claim 1, wherein the pegcomprises at least one of Rh and Ir.
 7. The recording head of claim 1,wherein all of the peg comprises at least one of Rh and Ir.
 8. Therecording head of claim 1, wherein a portion of the peg comprises atleast one of Rh and Ir.
 9. The recording head of claim 1, wherein thepeg has a thickness that is less than that of the base portion.
 10. Therecording head of claim 1, wherein the NFT is configured to receivetransverse electric (TE) mode light.
 11. The recording head of claim 1,wherein the NFT has a thickness that is less than that of the waveguide.12. A recording head, comprising: a near field transducer (NFT)comprising: a base portion; and a peg embedded in a part of the baseportion that faces a media-facing surface, the peg comprising anelongated outer part that extends from a lower edge of the enlargedportion towards the media-facing surface and an embedded part that isembedded within the base portion, the peg comprising a thermally robustmaterial; and a waveguide comprising a first core portion and a secondcore potion, the NFT disposed between the first waveguide core portionand the second waveguide core portion.
 13. The recording head of claim12, wherein NFT is a planar plasmon generator.
 14. The recording head ofclaim 12, wherein the NFT comprises a plasmonic material.
 15. Therecording head of claim 12, wherein the base portion and the pegcomprise different materials.
 16. The recording head of claim 12,wherein the peg comprises at least one of Rh and Ir.
 17. The recordinghead of claim 12, wherein all of the peg comprises at least one of Rhand Ir.
 18. The recording head of claim 12, wherein a portion of the pegcomprises at least one of Rh and Ir.
 19. The recording head of claim 12,wherein the peg has a thickness that is less than that of the baseportion.
 20. The recording head of claim 12, wherein the NFT isconfigured to receive transverse electric (TE) mode light.